Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2...
Transcript of Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2...
![Page 1: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/1.jpg)
Harnessing (roots and) soil biology
John KirkegaardCSIRO Plant Industry
![Page 2: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/2.jpg)
What is “soil biology”?
![Page 3: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/3.jpg)
Conservation farming - principles
● Minimum mechanical soil disturbance
● Permanent soil cover (crop or mulch)
● Diverse crop and pasture species
![Page 4: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/4.jpg)
Improving productivity of modern, no-till farming
Adoption is driven by
● Erosion control, water conservation
● Labour, machinery, fuel savings
● Timeliness of operations
● Soil “health” benefits
● Improved productivity
Llewellyn et al, (2012) Field Crops Research 132, 204-212
![Page 5: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/5.jpg)
Farming systems
Disturbed soil
UnderstandingLaboratory Undisturbed soil
The new environment for roots to perform
![Page 6: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/6.jpg)
500 m
rhizosphere
Wheat rootRoot hair
Image with cryo-scanning microscope, Watt et al., 2005
![Page 7: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/7.jpg)
Long-term study at Harden (25 years)
Improvements in soil parameters Good establishment Poor early vigour and yield
No-till/Retain vs Cultivate/Burn Wheat-Break crop 30 m x 6 m (4 replicates)
Growing season rainfall (mm)
0 100 200 300 400 500 600
Yiel
d di
ff (R
DD
-BC
) (t/h
a)
-1.5
-1.0
-0.5
0.0
0.5
1.0Yield gain
Yield loss
HARDEN
WAGGA
Kirkegaard (1995), (unpublished)
4 8 12 16 20 24
![Page 8: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/8.jpg)
Improving productivity in no-till
Strategies to improve productivity in intensive cereal systemsWhy do some varieties perform better?
Reducing impact of Rhizoctonia in no-till systemsUnderstanding biological suppression in soil
Investigating compatibility of livestock in no-till systemsImpacts of sheep on soil and water use
Improving organic-matter build-up in stubble retentionLimit may be nutrients rather than carbon input
Clive Kirkby
Hunt, Kirkegaard, Bell
Michelle Watt
VVSR Gupta
![Page 9: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/9.jpg)
Poor early vigour - biological constraints
No-till Cultivate No-tillFumigate
(Kirkegaard et al, 1997; Simpfendorfer et al, 2002)
Intact soil cores from field
![Page 10: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/10.jpg)
0
4
8
12
Cultivated No-till
Pseudomonasper mm root (x 103)
Cultivated soilFast growing roots
No- till soilSlow growing roots
Inhibitory bacteria on root tips in no-till soil
(Watt et al 2005, 2006)
![Page 11: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/11.jpg)
Options to improve crop vigour in no-till
Encourage rapid root growth
Sow early into warm soil
Disturb the soil below the seed using deep points
Select vigorous variety (Watt et al 2005)
![Page 12: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/12.jpg)
Strategic tillage – makes good sense
< 5% practice multiple cultivation pre-sowing
No-till adopters use cultivation on 30% area
88% use narrow points only (rather than discs)
Discs used to sow ~30% cropped area
GRDC 2010; Llewellyn et al 2012
Farmers adopt flexible approach to no-till
![Page 13: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/13.jpg)
Occasional tillage - irreparable soil damage..?
Case specific, but evidence is contested
Strategic tillage can resolve some issuesweed, disease management, lime incorporation (23M ha acid soils)
Recent study completed at Harden (Bissett et al, 2012)
microbial biomass, community structure, diversity and function(rDNA & rRNA, TRFLP)
diversity shifts across cropping cycle and treatments
little evidence of long term effects on biomass or function
![Page 14: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/14.jpg)
Soil carbon changes slow or absent
Rumpel (2008) no change after 31 years
Luo (2010) no difference in C at 69 paired sites
Stubble retention - the carbon “conundrum”.....
Rumpel et al (2008) J. Soil Sci. Pl. Nutr. 8, 44-51;
Luo et al (2010) Agric. Eco. Envir. 139, 224-31
What’s going on.....?
![Page 15: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/15.jpg)
Living(up to 10%)
Light Fraction(dead but active)
(up to 20%)
Soil Organic Matteror humus
(very dead)(up to 95%)
Soil Organic Material – where is the C?
![Page 16: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/16.jpg)
Its soil organic matter NOT carbon....
Target is stable organic matter (humus) NOT soil carbon
Stable organic matter has a constant ratio of C:N:P:S
Like bricks (C) and mortar (NPS) to build a stable brick wall
Nutrients (not C) might limit humus formation from residues
Dr Clive Kirkby PhD
![Page 17: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/17.jpg)
Stable organic matter has constant CNPS ratio
Total soil N (%)0.0 0.2 0.4 0.6 0.8 1.0 1.2
Tota
l soi
l C (%
)
0
2
4
6
8
10
12
14
16761 soils from various countries105 Australian soils collected from four of the five mainland states
r2=0.93
Total soil S (%)0.05 0.10 0.15 0.20
531 soils from various countries105 Australian soils collected from four of the five mainland states
r2=0.85
0
C:N C:S
500+ international and 100+ Australian soils
1000 lbs C requires 92 lbs N, 18 lbs P, 14 lbs S
Kirkby et al (2011) Geoderma 162, 197-208
![Page 18: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/18.jpg)
Nutrients increase C-sequestration from residue
Kirkby et al (2012)
Leeton
Incubation cycle0 1 2 3 4 5 6 7
Car
bon
(%)
1.5
2.0
2.5
3.0Soil + stubble + supplementary nutrientsSoil + stubble
error bars are SE
Repeated addition of 5 t/acre wheat straw (3 monthly)
Hum
us c
arbo
n %
5 t/acre wheat straw+ nutrients NPS
5 t/acre wheat straw
Laboratory incubation study (Harden soil)
(7 x 3-month cycles)
![Page 19: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/19.jpg)
Losing “old” soil C while making “new” carbon
Harden
Cha
ne in
car
bon
(mg
kg s
oil -1
)
-2000
0
2000
4000
6000
error bars are SE
+4
-29
-7% -7
+33%
+46%
-15
+31
new C gainedold C lostnet change
soil + straw soil + straw+ nutrients
soil alone(control)
5 t/acre equivalent C13-labelled straw added – single cycle
Kirkby et al (2012)
Soil only Soil + Straw Soil + Straw+ Nutrients NPS
![Page 20: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/20.jpg)
Buntine sand + stubble incubation (5 weeks)
Clive Kirkby (PhD)
![Page 21: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/21.jpg)
It works in the field – Harden field site
We mulch the stubble then
Add granular fertiliser to one plot
No fertiliser on adjoining plot
+ _
Incorporate stubble
+ _
![Page 22: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/22.jpg)
Humus-C increase of 7.5 t/ha after 3 years to 1.6 m
Carbon (t/ha)0 2 4 6 8 10 12
Dep
th (1
0 cm
incr
emen
ts)
123456789
10111213141516
stubble + nutrientsstubble
total C t/ha56.549.0
52% of C is below 30 cm
![Page 23: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/23.jpg)
Nutrient Amount (kg)
Approx price/kg nutrient Approx Cost ($)
N 92 1.50 138P 18 3.50 63S 14 1.00 14
$215
Implication – hidden cost of C-sequestration
Every 1 tonne of C-sequestered
requires
Australian government currently values CO2 at ~$23 / tonnethis equates to $84 per tonne of C
![Page 24: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/24.jpg)
Implications of nutrient ratios to build SOM....
C sequestration limited by nutrients, not C in no-till systems
Nutrient management in no-till (spray onto residue?)
Is strategic tillage necessary to sequester C from residues?
Nutrient-use efficiency vs C-sequestration?
Implications for:
manures, cover-crops, biochar, municipal wastes etc.....
![Page 25: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/25.jpg)
Crop and pasture sequence
![Page 26: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/26.jpg)
20 - 25 kg of shoot N fixed per tonne of legume biomass produced
at least 40% of N in cereals derives directly from previous legume N
high input of labile C and N in plant and organic animal residues
pasture increases organic carbon (~ 0.15% per year for 5 year)
improves soil structure (aggregate stability increase 5 -10%/yr)
Important biological impacts of legume-based pastures
![Page 27: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/27.jpg)
Broadleaf rotation crops (legumes, canola)
Disease control(root and stubble borne)
Weeds(control of grass weeds)
NitrogenLegumes (+20 to 50 kg/ha N)
Residues easy to retain
20% (0.5 t/ha) yield benefit
Water and nutrient efficiency
Kirkegaard et al (2008) Field Crops ResearchSeymour et al (2012) Crop and Pasture Science
![Page 28: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/28.jpg)
Root exudates, soil biology and crop growth
HUP- legumesH2 released into soil
(1500 gallons/ha/day)
Citrate release
White lupins
Brassicas
Isothiocyanates
Growth-promoting bacteria
(Peoples et al, 2008)
Improves P availability
(Hocking 2001)
Pathogen suppression
(Kirkegaard et al, 2008 )
![Page 29: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/29.jpg)
Not all break crops are equal
Previous cropWheat Oats Linseed Canola Mustard
Yie
ld (
t/ha
)
3.00
3.25
3.50
3.75
4.00
Kirkegaard et al (2008) Field Crops Research
![Page 30: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/30.jpg)
GFP-labelled fungus
Biofumigation – isothiocyanates from canola roots
glucosinolates Myrosinaseenzyme
Isothiocyanates(ITCs)
2 cmInside canola root
![Page 31: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/31.jpg)
Dale Gies, Moses Lake – potato disease control
Diseases managed
Verticillium wiltSclerotiniaRhizoctonia
StreptomycesNematodes
Mustard green manure replaced Metham sodium
√ Yield/quality maintained√ $US 169/ha saving√ Wind erosion control√ Increased water infiltration√ Improved soil organic matter√ CO2 saving 2t C/ha/yr (1.0 mill km by plane)
Andy McGuire WSU (2004); Dale Gies (2004)
USA – Pacific Northwest
35,000 ha green manure mustard
![Page 32: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/32.jpg)
But...intensive cereals dominate (64 to 80%)
Why cereals?easy to manage, market - low riskmore residues for cover/grazing
New technology helpsdisease resistance, soil/seed fungicides, soil DNA testingnew precision inter-row sowing, herbicide options
Yield penalties persist (5-10%)in absence of obvious disease, N or other known factorsevidence for bacterial involvementworth $200M pa
![Page 33: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/33.jpg)
5 mm
Live wheat crop roots
Dead roots frompreceding crop
Pore in no-till soil
(Watt et al., 2005; ME McCully, images)
No-till root environment....not all good!
Hard soil – no roots
![Page 34: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/34.jpg)
CarbonSugarsPhenolicsAcidsSignals
Last year’s dead roots Current roots
Microbial succession on old and new roots
Watt et al (2005)Cryo-scanning EMcourtesy: Margaret McCully
Actinomycetes
![Page 35: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/35.jpg)
Janz H45 Vig18TriticaleOats Janz H45 Vig18TriticaleOats Janz H45 Vig18TriticaleOats2006cereal
0
20
40
60
80
100
120
140
160
Janz Janz Janz Janz Janz H45 H45 H45 H45 H45 Vig18 Vig18 Vig18 Vig18 Vig18
Shoo
t dry
wei
ght i
ncre
ase
(% J
anz
on J
anz)
2007 wheatJanzH45V18
2007
Can rotating wheat varieties help?
Intact core studies
![Page 36: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/36.jpg)
Recent study on bacterial succession
Two-year wheat-wheat field study
Plating, T-RFLP, Pyrosequencing
Time (2 seasons)Variety (2)Soil type (2)Position (rhizoplane, rhizosphere, soil)
Outcomes Donn et al, 2012 (in preparation)
Position (space) and root age (time) significant determinants of populations
Season, soil type, previous crop, current genotype minor determinants
Inconsistent effects on growth and yield
![Page 37: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/37.jpg)
5 mm
Year 1 wheat Year 2 heat
Dead wheat root
Mixture young anddead roots
Young wheat root
0.01 mm
Bacteria labelled with DNA probes
Changes in microbe populations across sequence
![Page 38: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/38.jpg)
0
20
40
60
80
100
0
20
40
60
80
100
0
20
40
60
80
100
0
20
40
60
80
100
0
20
40
60
80
100
0
20
40
60
80
100
γ δ β α
Rhizobiaceae Caulobacteraceae BradyrhizobiaceaeSphingomonadaceae unclassif ied α-proteo incertae sedisPhyllobacteriaceae Hyphomicrobiaceae AcetobacteraceaeOther
Oxalobacteraceae Burkholderiales incertae sedisBurkholderiaceae Comamonadaceaeunclassif ied NeisseriaceaeOther
Pseudomonadaceae Xanthomonadaceae γ_unclass
Enterobacteriaceae Sinobacteraceae Other
Streptomycetaceae Microbacteriaceae unclassif iedMicromonosporaceae Kineosporiaceae NocardioidaceaePseudonocardiaceae Geodermatophilaceae Mycobacteriaceaeunclassif ied Micrococcaceae Other
FlavobacteriaceaeSphingobacteria_unclassCytophagaceaeCryomorphaceaeOther
SphingobacteriaceaeChitinophagaceaeunclassif iedBacteroidetes_incertae_sedis
Bacteroidetes
Proteobacteria
ActinobacteriaTB LB
Alpha-proteobacteria
Beta-proteobacteria
Gamma-proteobacteria
TB LB
%
Change in community composition with time and root compartment
OrderClassPhylum
Rhizoplane Rhizosphere(TB) (LB)
Assessment of the wheat root soil microbiome
unclassified Bacteroidetes Acidobacteria
Chloroflexi TM7 Firmicutes
Proteobacteria Actinobacteria other
0
20
40
60
80
100
gp
V1 R1 Sb V2 V1 R1 V2
year1 year2
The Challenge – How does community succession influence crop performance?
‐ nutrient availability‐ growth promotion‐ disease suppression
Can the microbiome be managed for agronomic benefit?
![Page 39: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/39.jpg)
3
-
-
“Not everything that is important can be measured,
and not everything that can be measured is important...”
Albert Einstien
Soil biology and health.........
![Page 40: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/40.jpg)
Roots for the future.....weed suppressive?
Wasson et al (2012) J. Exp. Bot. 63, 3325-33
Sorgoleone onsorghum root tips
![Page 41: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/41.jpg)
New frontier - root-soil biology research
● Synergies from …
new root genetics
precision placement
novel input/formulations
Understanding
Farming systems
Lab Tilled No-till
Further gains in efficiency and productivity
![Page 42: Harnessing (roots and) soil biologyTotal soil N (%) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Total soil C (%) 0 2 4 6 8 10 12 14 16 761 soils from various countries 105 Australian soils collected](https://reader034.fdocuments.in/reader034/viewer/2022043018/5f3af666f5f6d12e730d4f6c/html5/thumbnails/42.jpg)
Thank youCSIRO Plant IndustryJohn Kirkegaard
Email: [email protected]
Contact UsPhone: 1300 363 400 or +61 3 9545 2176Email: [email protected] Web: www.csiro.au
Many colleagues, farmers and friends.....